This django/python/heroku app is a basic example to get ical from one address, modify the events and render the output again. See https://github.com/holli/icalendar_modifier/blob/master/modifiers/views.py#L56
I'm having all my Facebook events in my Google calendar. Works fine except some people make events like "winter practices" that clutter calendar view. So now I route some of my calendar imports through this app to change multiday events to singleday.
Live at https://icalendar-modifier.herokuapp.com/
Make sure you have Python installed properly. Also, install the Heroku Toolbelt.
$ pip install -r requirements.txt
$ foreman start web
$ python manage.py runserver
or
$ python manage.py runserver
Your app should now be running on localhost:5000.
$ heroku create
$ git push heroku master
$ heroku run python manage.py migrate
$ heroku open
$ heroku logs --tail